Cowl for ventilating and other purposes.



S. EWART.

GOWL r011 VENTILATING AND OTHER PURPOSES.

APPLIUATION FILED JULY 1, 1910.

Patented Dec. 20, 1910.

\ n l l l lH l hP Hl O l nu: NORRIS PETERS qu., wasmus'rou, 'a c.

SAMUEL EWAR'I, OF LONDON, ENGLAND.

COWL FOR VENTILATING AND OTHER PURPOSES.

Specification of Letters Patent.

Application filed July 1, 1910.

Patented Dec. 20, 1910.

Serial No. 569,931.

T 0 all whom it may concern:

Be it known that I, SAMUEL EWART, a subject of the King of Great-Britain, residing at 3&6, 3&8, and 350 Euston road, London, England,have invented new and useful Improvements in Cowls for Ventilating andother Purposes, of which the following is a specification.

My invention relates to cowls for ventilating purposes and forpreventing down draft in chimneys or ventilating pipes or shafts, and tothat class of cowl provided with a rotating head having upon ita numberof blades or vanes against which the wind acts to cause the rotation,the object of my invention being to render such cowls more eiiicient inoperation than heretofore.

In the cowl constructed according to my invention the blades or vanesare approximately of ogee shape in horizontal section, and extend from aring which forms the lower end of the head up to the apex of the coneforming the upper part of the head, the said blades being bent or shapedto lie with their inner edges upon the said ring and cone. The outeredges of the said blades are in a vertical or substantially verticalposition from the lower to the upper end, and the concavities on thefront faces which catch the wind are adjacent to the outer edges, whilethe concavities on the rear faces of the blades serve to direct any windwhich strikes them into the concavities of the front faces of theadjacent blades, so as to assist in rotating the hood without theliability of the wind blowing directly into the said hood between theblades. The concavity of the outer portions of the blades adjacent tothe edges is also such that the rear or convex sides of these outerportions slope rapidly back away from the outer edges.

To enable the invention to be fully understood, I will describe it byreference to the accompanying drawing, in which Figure 1 is a sectionalelevation of a cowl constructed according to my invention. Fig. 2 is asectional plan view thereof. Fig. 3 is a section on the line 33, Fig. 1,viewed in the direction of the arrow, and Fig. 4 is a vertical sectionillustrating a detail.

a is a stationary portion of the cowl, b the ring which forms the lowerend of the head, and 0 the cone which forms the upper part of the headthereof. This cone Z) is connected at its upper part to the bridgepieceZ) secured to the upper end of the pivot spindle b the said spindlepasses through the bearing bush or sleeve 72 to the upper part of whichis attached the oil cup 6 also traversed by the spindle.

(Z, (Z are the. blades or vanes, each of the said blades being connectedat its lower end to the aforesaid ring I), and at its upper end to theapex of the cone 0. Each of the blades (Z' is bent or shaped so as tolie with its inner edge upon the ring or cone, its outer edge beingvertical, or substantially vertical as will be clearly seen by referenceto the drawing. Furthermore, each blade is so shape-d that it presentstwo concavities, that is to say, a concavity 6 adjacent to the outeredge on the front face, and a concavity f on the rear face.

As above described, the concavities e are designed to catch the wind forthe purpose of rotating the cowl, while the concavities f are designedto deflect any wind which may strike them into the concavities e of theadjacent blades, thereby assisting in rotating the hood and preventingwind blowing directly into the same between the blades (Z, (Z.

It will also be seen that the concavities 6 adjacent to the outer edgesof the blades slope rapidly back away from the said outer edges whenmerging into the concavities f.

Cowls made as above described are more efficient in operation than cowlsof this type as hitherto made owing to the special construction of theblades, which not only prevent wind blowing directly into the hood butalso lessen the resistance to rotation owing to their ogee shape thusenabling the cowls to remain in motion under the action of a gust ofwind longer than is possible with cowls as heretofore made.

Claims.

1. A. cowl of the class described, comprising blades of approximatelyogee shape in horizontal cross section, a cone and a ring, the mainportion of said blades extending vertically and set substantially in atangential position with their lower ends secured to said ring, andtheir upper portions extending inwardly over and upon the said cone andsecured to the upper end thereof, substantially as described.

2. A cowl of the class described, comprising blades of approximatelyogee shape in transverse sect-ion, a cone and a ring, the main part ofsaid blades extending verticavity on the front face of the next adjacentblade, substantially as described.

SAMUEL EWART.

Witnesses J OHN E. BONSFIELD, C. G. REDFERN.

